From: "Gustavo A. R. Silva" gustavoars@kernel.org
[ Upstream commit 820aa37638a252b57967bdf4038a514b1ab85d45 ]
Fix the following out-of-bounds warnings by enclosing structure members daddr and saddr into new struct addr, in structures wl3501_md_req and wl3501_md_ind:
arch/x86/include/asm/string_32.h:182:25: warning: '__builtin_memcpy' offset [18, 23] from the object at 'sig' is out of the bounds of referenced subobject 'daddr' with type 'u8[6]' {aka 'unsigned char[6]'} at offset 11 [-Warray-bounds] arch/x86/include/asm/string_32.h:182:25: warning: '__builtin_memcpy' offset [18, 23] from the object at 'sig' is out of the bounds of referenced subobject 'daddr' with type 'u8[6]' {aka 'unsigned char[6]'} at offset 11 [-Warray-bounds]
Refactor the code, accordingly:
$ pahole -C wl3501_md_req drivers/net/wireless/wl3501_cs.o struct wl3501_md_req { u16 next_blk; /* 0 2 */ u8 sig_id; /* 2 1 */ u8 routing; /* 3 1 */ u16 data; /* 4 2 */ u16 size; /* 6 2 */ u8 pri; /* 8 1 */ u8 service_class; /* 9 1 */ struct { u8 daddr[6]; /* 10 6 */ u8 saddr[6]; /* 16 6 */ } addr; /* 10 12 */
/* size: 22, cachelines: 1, members: 8 */ /* last cacheline: 22 bytes */ };
$ pahole -C wl3501_md_ind drivers/net/wireless/wl3501_cs.o struct wl3501_md_ind { u16 next_blk; /* 0 2 */ u8 sig_id; /* 2 1 */ u8 routing; /* 3 1 */ u16 data; /* 4 2 */ u16 size; /* 6 2 */ u8 reception; /* 8 1 */ u8 pri; /* 9 1 */ u8 service_class; /* 10 1 */ struct { u8 daddr[6]; /* 11 6 */ u8 saddr[6]; /* 17 6 */ } addr; /* 11 12 */
/* size: 24, cachelines: 1, members: 9 */ /* padding: 1 */ /* last cacheline: 24 bytes */ };
The problem is that the original code is trying to copy data into a couple of arrays adjacent to each other in a single call to memcpy(). Now that a new struct _addr_ enclosing those two adjacent arrays is introduced, memcpy() doesn't overrun the length of &sig.daddr[0] and &sig.daddr, because the address of the new struct object _addr_ is used, instead.
This helps with the ongoing efforts to globally enable -Warray-bounds and get us closer to being able to tighten the FORTIFY_SOURCE routines on memcpy().
Link: https://github.com/KSPP/linux/issues/109 Reported-by: kernel test robot lkp@intel.com Reviewed-by: Kees Cook keescook@chromium.org Signed-off-by: Gustavo A. R. Silva gustavoars@kernel.org Signed-off-by: Kalle Valo kvalo@codeaurora.org Link: https://lore.kernel.org/r/d260fe56aed7112bff2be5b4d152d03ad7b78e78.161844226... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/wireless/wl3501.h | 12 ++++++++---- drivers/net/wireless/wl3501_cs.c | 10 ++++++---- 2 files changed, 14 insertions(+), 8 deletions(-)
diff --git a/drivers/net/wireless/wl3501.h b/drivers/net/wireless/wl3501.h index b446cb369557..31ebef3e7ed4 100644 --- a/drivers/net/wireless/wl3501.h +++ b/drivers/net/wireless/wl3501.h @@ -471,8 +471,10 @@ struct wl3501_md_req { u16 size; u8 pri; u8 service_class; - u8 daddr[ETH_ALEN]; - u8 saddr[ETH_ALEN]; + struct { + u8 daddr[ETH_ALEN]; + u8 saddr[ETH_ALEN]; + } addr; };
struct wl3501_md_ind { @@ -484,8 +486,10 @@ struct wl3501_md_ind { u8 reception; u8 pri; u8 service_class; - u8 daddr[ETH_ALEN]; - u8 saddr[ETH_ALEN]; + struct { + u8 daddr[ETH_ALEN]; + u8 saddr[ETH_ALEN]; + } addr; };
struct wl3501_md_confirm { diff --git a/drivers/net/wireless/wl3501_cs.c b/drivers/net/wireless/wl3501_cs.c index 8ca5789c7b37..70307308635f 100644 --- a/drivers/net/wireless/wl3501_cs.c +++ b/drivers/net/wireless/wl3501_cs.c @@ -469,6 +469,7 @@ static int wl3501_send_pkt(struct wl3501_card *this, u8 *data, u16 len) struct wl3501_md_req sig = { .sig_id = WL3501_SIG_MD_REQ, }; + size_t sig_addr_len = sizeof(sig.addr); u8 *pdata = (char *)data; int rc = -EIO;
@@ -484,9 +485,9 @@ static int wl3501_send_pkt(struct wl3501_card *this, u8 *data, u16 len) goto out; } rc = 0; - memcpy(&sig.daddr[0], pdata, 12); - pktlen = len - 12; - pdata += 12; + memcpy(&sig.addr, pdata, sig_addr_len); + pktlen = len - sig_addr_len; + pdata += sig_addr_len; sig.data = bf; if (((*pdata) * 256 + (*(pdata + 1))) > 1500) { u8 addr4[ETH_ALEN] = { @@ -980,7 +981,8 @@ static inline void wl3501_md_ind_interrupt(struct net_device *dev, } else { skb->dev = dev; skb_reserve(skb, 2); /* IP headers on 16 bytes boundaries */ - skb_copy_to_linear_data(skb, (unsigned char *)&sig.daddr, 12); + skb_copy_to_linear_data(skb, (unsigned char *)&sig.addr, + sizeof(sig.addr)); wl3501_receive(this, skb->data, pkt_len); skb_put(skb, pkt_len); skb->protocol = eth_type_trans(skb, dev);